// Sum.java public class Sum { public static void main(String[] args) { int sum = 0; for (String argument : args) { StringBuilder number = new StringBuilder(); // we will form numbers here using StringBuilder for (char c : argument.toCharArray()) { if (!Character.isWhitespace(c)) { // if character is not whitespace number.append(c); // concatenate new digit } else { // if character is whitespace if (!number.isEmpty()) { // if number is not empty sum = sum + Integer.parseInt(number.toString()); // add number to sum } number = new StringBuilder(); // empty the number by creating new empty StringBuilder } } // check for any remaining digits in number if (!number.isEmpty()) { // if number is not empty sum = sum + Integer.parseInt(number.toString()); // add number to sum } } System.out.println(sum); } }